1. Field of the Invention
The present invention relates to a method and device for testing the quality of a ground path, particularly although not exclusively for a telecommunications system.
2. Introduction to the Invention
Telecommunications systems are generally grounded at central offices, etc., and also at various other points throughout the network. These other grounds are referred to in this specification as local grounds. It is testing of the quality of the path between, for example a local ground and a remote ground that is the principal subject of this invention. Poor quality ground paths may result from a variety of causes including low soil conductivity or the presence in the locality of ground return paths to power generating stations, etc.
As a result, a local ground might not be at the same potential as the remote ground at the central office, etc. This phenomenon may be referred to as a ground potential rise. A ground potential rise can cause malfunctioning of electrical systems and can be dangerous to workers during installation, maintenance or use. The problem is known, and workers typically test for it by connecting a meter between the local ground and some relevant part of the electrical system under test (such as the lines of a telecommunications system). A particular reading on the meter will indicate that a problem exists, but the severity of the problem will not be immediately apparent.
Meters are often unreliable or need calibrating. Also, there is no widely accepted standard as to what local ground voltage is acceptable, what should be logged for future routine investigation, and what should give rise to immediate emergency correction.